/*
* Copyright (c) 2008 Thierry Coppey, EPFL
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*     * Redistributions of source code must retain the above copyright
*       notice, this list of conditions and the following disclaimer.
*     * Redistributions in binary form must reproduce the above copyright
*       notice, this list of conditions and the following disclaimer in the
*       documentation and/or other materials provided with the distribution.
*     * Neither the name of Thierry Coppey nor EPFL, nor the
*       names of its contributors may be used to endorse or promote products
*       derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THIERRY COPPEY AND EPFL ''AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THIERRY COPPEY OR EPFL BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/bpf.h>
#include <net/if.h>

#define ERR(MSG) { perror(MSG); free(buf); close(fd); return 1; }
#define BUFSIZE 8192

int main(int argc, char* argv[]) {
	int i,len,sz=BUFSIZE,fd=-1; char path[32]; void* buf=0; struct ifreq ifr;

	if (argc<2) { printf("usage : %s <if_name>\n",argv[0]); return 1; }
	if (!strcmp(argv[1],"--setuid")) exit(chown(argv[0],0,0)||chmod(argv[0],04755));

	strlcpy(ifr.ifr_name,argv[1],sizeof(ifr.ifr_name));
	for (i=0;fd==-1&&i<10;i++) { snprintf(path,32,"/dev/bpf%d",i); fd=open(path,O_RDONLY); }

	if (fd<0) ERR("cannot open any BPF");
	if (ioctl(fd,BIOCSBLEN,&sz)<0) ERR("cannot set buffer size");
	if (!(buf=malloc(sz))) ERR("cannot alloc memory");
	if (ioctl(fd,BIOCSETIF,(caddr_t)&ifr)<0) ERR("cannot set interface");
	if (ioctl(fd,BIOCPROMISC,0)<0) ERR("cannot enter promisc mode");

	//i=1; ioctl(fd,BIOCIMMEDIATE,&i);

	while(1) if((len=read(fd,buf,sz))>0&&write(1,buf,len)==-1) break;
	free(buf); close(fd); return 0;
}
